Translator’s Note: The material between square brackets is explanatory in nature and is not part of Luther’s preface. The terms “just, justice, justify” in this piece are synonymous with the terms “righteous, righteousness, make righteous.” Both sets of English words are common translations of German “gerecht” and related words. A similar situation exists with the word “faith”; it is synonymous with “belief.” Both words can be used to translate German “Glaube.” Thus, “We are justified by faith” translates the same original German sentence as does “We are made righteous by belief.”

This letter is truly the most important piece in the New Testament. It is purest Gospel. It is well worth a Christian’s while not only to memorize it word for word but also to occupy himself with it daily, as though it were the daily bread of the soul. It is impossible to read or to meditate on this letter too much or too well. The more one deals with it, the more precious it becomes and the better it tastes. Therefore I want to carry out my service and, with this preface, provide an introduction to the letter, insofar as God gives me the ability, so that every one can gain the fullest possible understanding of it. Up to now it has been darkened by glosses [explanatory notes and comments which accompany a text] and by many a useless comment, but it is in itself a bright light, almost bright enough to illumine the entire Scripture.

To begin with, we have to become familiar with the vocabulary of the letter and know what St. Paul means by the words law, sin, grace, faith, justice, flesh, spirit, etc. Otherwise there is no use in reading it.

You must not understand the word law here in human fashion, i.e., a regulation about what sort of works must be done or must not be done. That’s the way it is with human laws: you satisfy the demands of the law with works, whether your heart is in it or not. God judges what is in the depths of the heart. Therefore his law also makes demands on the depths of the heart and doesn’t let the heart rest content in works; rather it punishes as hypocrisy and lies all works done apart from the depths of the heart. All human beings are called liars (Psalm 116), since none of them keeps or can keep God’s law from the depths of the heart. Everyone finds inside himself an aversion to good and a craving for evil. Where there is no free desire for good, there the heart has not set itself on God’s law. There also sin is surely to be found and the deserved wrath of God, whether a lot of good works and an honorable life appear outwardly or not.

Therefore in chapter 2, St. Paul adds that the Jews are all sinners and says that only the doers of the law are justified in the sight of God. What he is saying is that no one is a doer of the law by works. On the contrary, he says to them, “You teach that one should not commit adultery, and you commit adultery. You judge another in a certain matter and condemn yourselves in that same matter, because you do the very same thing that you judged in another.” It is as if he were saying, “Outwardly you live quite properly in the works of the law and judge those who do not live the same way; you know how to teach everybody. You see the speck in another’s eye but do not notice the beam in your own.”

Outwardly you keep the law with works out of fear of punishment or love of gain. Likewise you do everything without free desire and love of the law; you act out of aversion and force. You’d rather act otherwise if the law didn’t exist. It follows, then, that you, in the depths of your heart, are an enemy of the law. What do you mean, therefore, by teaching another not to steal, when you, in the depths of your heart, are a thief and would be one outwardly too, if you dared. (Of course, outward work doesn’t last long with such hypocrites.) So then, you teach others but not yourself; you don’t even know what you are teaching. You’ve never understood the law rightly. Furthermore, the law increases sin, as St. Paul says in chapter 5. That is because a person becomes more and more an enemy of the law the more it demands of him what he can’t possibly do.

In chapter 7, St. Paul says, “The law is spiritual.” What does that mean? If the law were physical, then it could be satisfied by works, but since it is spiritual, no one can satisfy it unless everything he does springs from the depths of the heart. But no one can give such a heart except the Spirit of God, who makes the person be like the law, so that he actually conceives a heartfelt longing for the law and henceforward does everything, not through fear or coercion, but from a free heart. Such a law is spiritual since it can only be loved and fulfilled by such a heart and such a spirit. If the Spirit is not in the heart, then there remain sin, aversion and enmity against the law, which in itself is good, just and holy.